The virulent E. coli O157:H7 bacteria could be enlisting the help of formerly harmless intestinal bacteria to cause some lethal side effects say researchers from the University of Cincinnati and Cincinnati Children's Hospital Medical Center. Their findings appear in the June 2003 issue of the journal Infection and Immunity.
E. coli O157:H7 bacteria are a common cause of gastrointestinal disease which in some cases can lead to hemolytic uremic syndrome (HUS), which results in acute kidney failure in children. Antibiotic treatment of the infection can trigger progression to HUS in some cases but not in others. The reason for this is not known, but the production of shiga toxin by the bacteria is believed to be involved.
In the study, the researchers found that E. coli O157:H7 bacteria, when killed by antibiotics, not only released shiga toxin, but also a bacteriophage, a virus that infects other bacteria, that contained the genetic code for production of the toxin. The phage would then infect the harmless E. coli bacteria that normally inhabit the intestines, causing them to produce more shiga toxin and more phage, which would infect more bacteria and continue the cycle.
(S. D. Gamage, J. E. Strasser, C. L. Chalk, A. A. Weiss. 2003. Nonpathogenic Escherichia coli can contribute to the production of Shiga toxin. Infection and Immunity, 71. 6: 3107-3115.)
Herpesvirus may cause lung disease
A herpesvirus may contribute to the development of a fatal lung disease say researchers from Vanderbilt University, Meharry Medical College, Duke University Medical Center, National Institutes of Health, and Emory University School of Medicine. Their findings appear in the June 2003 issue of the Journal of Clinical Microbiology.